如何在 C# 中设置/使用 VPN？

using System;
using System.Runtime.InteropServices;

public class VPN
{
    [DllImport("CiscoAnyConnectSecureMobilityClient.dll")]
    public static extern int AcConnect(string profile);

    [DllImport("CiscoAnyConnectSecureMobilityClient.dll")]
    public static extern int AcDisconnect();
}

public class Program
{
    public static void Main(string[] args)
    {
        string profile = "vpn://example.com/profile";
        int result = VPN.AcConnect(profile);
        if (result == 0)
        {
            Console.WriteLine("VPN连接成功");
        }
        else
        {
            Console.WriteLine("VPN连接失败");
        }
    }
}

using System.Net.Http;
using System.Threading.Tasks;

public class Program
{
    public static async Task Main(string[] args)
    {
        string url = "https://example.com";
        using (HttpClient httpClient = new HttpClient())
        {
            HttpResponseMessage response = await httpClient.GetAsync(url);
            if (response.IsSuccessStatusCode)
            {
                string content = await response.Content.ReadAsStringAsync();
                Console.WriteLine(content);
            }
            else
            {
                Console.WriteLine("请求失败");
            }
        }
    }
}